Patch tracker / KB5002820
KB5002820: Office Online Server Security Update (December 2025)
Microsoft security update released 2025-12-09. Fixes 6 CVEs.
All about KB5002820: the download, the Senserva AI read, install guidance, the CVEs it fixes, and its change history.
Which of your devices are missing it? Find out free with a full Microsoft 365 audit.
KB5002820 is a High security update for Office Online Server, released 2025-12-09. It closes 6 CVEs with a maximum CVSS of 7.8. Get it from the Microsoft Update Catalog below, and see where it sits against the rest of the month on the patch tracker.
No exploitation is confirmed for the CVEs in this update and the EPSS exploitation probability is currently <1%. That can change: CVEs from past updates regularly get exploited months later, which is why deploying on your normal cadence, without exceptions that linger, is what keeps this one boring.
Most organizations deliver an update like this automatically through Intune update rings, Windows Update for Business, Windows Autopatch, or WSUS; the install section below covers each path. For the bigger picture: how the Microsoft patching tools fit together, this month's Patch Tuesday summary, and every update ranked by real-world risk.
Download KB5002820
Get the official update for KB5002820. The download and file size for each supported product are on the Microsoft Update Catalog page.
Update summary
Senserva AI Opinion for KB5002820
December 2025's KB5002820 is a heavy Office Online Server and Office 2019 update, closing six CVEs at once, CVE-2025-62561, -62563, -62564, -62553, -62556, and -62560, the worst rated High at CVSS 7.8. Consolidating six fixes into one release makes this one of the more consequential Office updates in the batch and worth prioritizing in year-end patching.
Do this: Prioritize KB5002820 for Office Online Server and Office 2019 given the six CVEs it resolves.
AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for KB5002820
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for KB5002820
Senserva began recording day-to-day change history on 2026-07-07, and refreshes it several times a day. Release dates are historical where Microsoft publishes them; revision history is tracked from that date forward, so it does not include changes made before then.
Exploitation and severity
Fixes 6 CVEs. Most severe CVSS 7.8 (High). EPSS exploit probability up to <1%.
Among the lower half of tracked Microsoft updates by EPSS exploit probability.
What to do
Moderate priority: schedule it in your normal patch cycle. Senserva flags whether KB5002820 is missing on your devices.
CVEs fixed by this update
Affected products
Also released in December 2025
The highest-risk updates from the same release:
The full month, summarized: Microsoft Patch Tuesday.
How to install KB5002820
Any of these paths delivers KB5002820; most organizations already have one of the first three running:
- Intune update rings (Windows Update for Business): the update flows on each ring's deferral schedule.
- Windows Autopatch: rings, rollout, and pause or rollback are managed for you; exploited updates can be expedited.
- WSUS / Configuration Manager: approve KB5002820 for your device groups and set a deadline.
- Manual: download from the Update Catalog above and install; fine for a handful of machines, unmanageable at any real scale.
After the rollout, verify rather than assume: update compliance reporting in Intune or Autopatch shows which devices actually installed it, and Siemserva reads Intune, Defender, Autopatch, and Azure Update Manager together to show the devices still missing KB5002820, ranked by exploitation.
Common questions about KB5002820
Is KB5002820 urgent?
KB5002820 is rated High. Include it in your normal patch cycle unless your environment raises its priority.
How do I download KB5002820?
From the Microsoft Update Catalog (linked on this page), or let Intune, Windows Update for Business, Windows Autopatch, or WSUS deliver it. The catalog page lists the download for each supported product.
How do I deploy KB5002820 with Intune?
Assign a Windows Update ring (quality update policy) to the device groups and the update flows on the ring's deferral schedule. For urgent updates, Intune expedite policies can bypass the ring deferrals. Verify the rollout with update compliance reporting rather than assuming delivery.
Can I ask my own AI about KB5002820?
Yes. This page includes a free, ready-to-paste AI prompt containing KB5002820's key facts: severity, CVE count, exploitation status, and the download link. Copy it into Claude, ChatGPT, or Copilot for a rollout plan; the data is refreshed three times a day (5 AM, 12:30 PM, and 7 PM US Central).
Authoritative references
See this and every Microsoft update ranked by real-world risk on the Microsoft Patch Tracker.
